org.apache.velocity.runtime

Interface RuntimeServices

All Known Implementing Classes:

RuntimeInstance

public interface RuntimeServices

Interface for internal runtime services that are needed by the various components w/in Velocity. This was taken from the old Runtime singleton, and anything not necessary was removed. Currently implemented by RuntimeInstance.

Version:

$Id: RuntimeServices.java 1780734 2017-01-28 19:21:08Z cbrisson $

Author:

Geir Magusson Jr.

Method Summary

Modifier and Type	Method and Description
void	addProperty(String key, Object value) Add a property to the configuration.
boolean	addVelocimacro(String name, Node macro, List<Macro.MacroArg> macroArgs, Template definingTemplate) Adds a new Velocimacro.
void	clearProperty(String key) Clear the values pertaining to a particular property.
Parser	createNewParser() Create a new parser instance.
boolean	evaluate(Context context, Writer writer, String logTag, Reader reader) Renders the input reader using the context into the output writer.
boolean	evaluate(Context context, Writer out, String logTag, String instring) Renders the input string using the context into the output writer.
Object	getApplicationAttribute(Object key) Return the specified application attribute.
EventCartridge	getApplicationEventCartridge() Returns the event handlers for the application.
boolean	getBoolean(String key, boolean def) Boolean property accessor method to hide the configuration implementation.
ExtProperties	getConfiguration() Return the velocity runtime configuration object.
ContentResource	getContent(String name) Returns a static content resource from the resource manager.
ContentResource	getContent(String name, String encoding) Returns a static content resource from the resource manager.
Directive	getDirective(String name) Retrieve a previously instantiated directive.
int	getInt(String key) Int property accessor method to hide the configuration implementation.
int	getInt(String key, int defaultValue) Int property accessor method to hide the configuration implementation.
String	getLoaderNameForResource(String resourceName) Determines is a template exists, and returns name of the loader that provides it.
org.slf4j.Logger	getLog() Returns a convenient Log instance that wraps the current LogChute.
org.slf4j.Logger	getLog(String childNamespace) Get a logger for the specified child namespace.
Object	getProperty(String key) Allows an external caller to get a property.
RuntimeConstants.SpaceGobbling	getSpaceGobbling() get space gobbling mode
String	getString(String key) String property accessor method to hide the configuration implementation
String	getString(String key, String defaultValue) String property accessor method with default to hide the configuration implementation.
Template	getTemplate(String name) Returns a Template from the resource manager.
Template	getTemplate(String name, String encoding) Returns a Template from the resource manager
Uberspect	getUberspect() Returns the configured class introspection/reflection implementation.
Directive	getVelocimacro(String vmName, Template renderingTemplate, Template template) Returns the appropriate VelocimacroProxy object if strVMname is a valid current Velocimacro.
void	init() This is the primary initialization method in the Velocity Runtime.
void	init(Properties p) Initialize the Velocity Runtime with a Properties object.
void	init(String configurationFile) Initialize the Velocity Runtime with the name of ExtProperties object.
boolean	invokeVelocimacro(String vmName, String logTag, String[] params, Context context, Writer writer) Invokes a currently registered Velocimacro with the params provided and places the rendered stream into the writer.
boolean	isInitialized() Returns true if the RuntimeInstance has been successfully initialized.
boolean	isVelocimacro(String vmName, Template template) Checks to see if a VM exists
SimpleNode	parse(Reader reader, Template template) Parse the input and return the root of AST node structure.
Object	setApplicationAttribute(Object key, Object value) Set the specified application attribute.
void	setConfiguration(ExtProperties configuration) Allow an external system to set an ExtProperties object to use.
void	setProperty(String key, Object value) Allows an external system to set a property in the Velocity Runtime.
boolean	useStringInterning() Check whether the engine uses string interning

Method Detail

init

void init()

This is the primary initialization method in the Velocity Runtime. The systems that are setup/initialized here are as follows:

• Logging System
• ResourceManager
• Parser Pool
• Global Cache
• Static Content Include System
• Velocimacro System

setProperty

void setProperty(String key,
                 Object value)

Allows an external system to set a property in the Velocity Runtime.

Parameters:

key - property key

value - property value

setConfiguration

void setConfiguration(ExtProperties configuration)

Allow an external system to set an ExtProperties object to use.

Parameters:

configuration -

Since:

2.0

addProperty

void addProperty(String key,
                 Object value)

Add a property to the configuration. If it already exists then the value stated here will be added to the configuration entry. For example, if resource.loader = file is already present in the configuration and you addProperty("resource.loader", "classpath") Then you will end up with a Vector like the following: ["file", "classpath"]

Parameters:

key -

value -

clearProperty

void clearProperty(String key)

Clear the values pertaining to a particular property.

Parameters:

key - of property to clear

getProperty

Object getProperty(String key)

Allows an external caller to get a property. The calling routine is required to know the type, as this routine will return an Object, as that is what properties can be.

Parameters:

key - property to return

Returns:

The value.

init

void init(Properties p)

Initialize the Velocity Runtime with a Properties object.

Parameters:

p -

init

void init(String configurationFile)

Initialize the Velocity Runtime with the name of ExtProperties object.

Parameters:

configurationFile -

parse

SimpleNode parse(Reader reader,
                 Template template)
          throws ParseException

Parse the input and return the root of AST node structure.

In the event that it runs out of parsers in the pool, it will create and let them be GC'd dynamically, logging that it has to do that. This is considered an exceptional condition. It is expected that the user will set the PARSER_POOL_SIZE property appropriately for their application. We will revisit this.

Parameters:

reader - inputstream retrieved by a resource loader

template - template being parsed

Returns:

The AST representing the template.

Throws:

ParseException

evaluate

boolean evaluate(Context context,
                 Writer out,
                 String logTag,
                 String instring)

Renders the input string using the context into the output writer. To be used when a template is dynamically constructed, or want to use Velocity as a token replacer.

Parameters:

context - context to use in rendering input string

out - Writer in which to render the output

logTag - string to be used as the template name for log messages in case of error

instring - input string containing the VTL to be rendered

Returns:

true if successful, false otherwise. If false, see Velocity runtime log

Throws:

ParseErrorException - The template could not be parsed.

MethodInvocationException - A method on a context object could not be invoked.

ResourceNotFoundException - A referenced resource could not be loaded.

IOException - While rendering to the writer, an I/O problem occurred.

Since:

Velocity 1.6

evaluate

boolean evaluate(Context context,
                 Writer writer,
                 String logTag,
                 Reader reader)

Renders the input reader using the context into the output writer. To be used when a template is dynamically constructed, or want to use Velocity as a token replacer.

Parameters:

context - context to use in rendering input string

writer - Writer in which to render the output

logTag - string to be used as the template name for log messages in case of error

reader - Reader containing the VTL to be rendered

Returns:

true if successful, false otherwise. If false, see Velocity runtime log

Throws:

ParseErrorException - The template could not be parsed.

MethodInvocationException - A method on a context object could not be invoked.

ResourceNotFoundException - A referenced resource could not be loaded.

Since:

Velocity 1.6

invokeVelocimacro

boolean invokeVelocimacro(String vmName,
                          String logTag,
                          String[] params,
                          Context context,
                          Writer writer)

Invokes a currently registered Velocimacro with the params provided and places the rendered stream into the writer.
Note : currently only accepts args to the VM if they are in the context.

Parameters:

vmName - name of Velocimacro to call

logTag - string to be used for template name in case of error. if null, the vmName will be used

params - keys for args used to invoke Velocimacro, in java format rather than VTL (eg "foo" or "bar" rather than "$foo" or "$bar")

context - Context object containing data/objects used for rendering.

writer - Writer for output stream

Returns:

true if Velocimacro exists and successfully invoked, false otherwise.

Since:

1.6

getTemplate

Template getTemplate(String name)
              throws ResourceNotFoundException,
                     ParseErrorException

Returns a Template from the resource manager. This method assumes that the character encoding of the template is set by the input.encoding property. The default is UTF-8.

Parameters:

name - The file name of the desired template.

Returns:

The template.

Throws:

ResourceNotFoundException - if template not found from any available source.

ParseErrorException - if template cannot be parsed due to syntax (or other) error.

getTemplate

Template getTemplate(String name,
                     String encoding)
              throws ResourceNotFoundException,
                     ParseErrorException

Returns a Template from the resource manager

Parameters:

name - The name of the desired template.

encoding - Character encoding of the template

Returns:

The template.

Throws:

ResourceNotFoundException - if template not found from any available source.

ParseErrorException - if template cannot be parsed due to syntax (or other) error.

getContent

ContentResource getContent(String name)
                    throws ResourceNotFoundException,
                           ParseErrorException

Returns a static content resource from the resource manager. Uses the current value if INPUT_ENCODING as the character encoding.

Parameters:

name - Name of content resource to get

Returns:

parsed ContentResource object ready for use

Throws:

ResourceNotFoundException - if template not found from any available source.

ParseErrorException

getContent

ContentResource getContent(String name,
                           String encoding)
                    throws ResourceNotFoundException,
                           ParseErrorException

Returns a static content resource from the resource manager.

Parameters:

name - Name of content resource to get

encoding - Character encoding to use

Returns:

parsed ContentResource object ready for use

Throws:

ResourceNotFoundException - if template not found from any available source.

ParseErrorException

getLoaderNameForResource

String getLoaderNameForResource(String resourceName)

Determines is a template exists, and returns name of the loader that provides it. This is a slightly less hokey way to support the Velocity.templateExists() utility method, which was broken when per-template encoding was introduced. We can revisit this.

Parameters:

resourceName - Name of template or content resource

Returns:

class name of loader than can provide it

getString

String getString(String key,
                 String defaultValue)

String property accessor method with default to hide the configuration implementation.

Parameters:

key - property key

defaultValue - default value to return if key not found in resource manager.

Returns:

String value of key or default

getVelocimacro

Directive getVelocimacro(String vmName,
                         Template renderingTemplate,
                         Template template)

Returns the appropriate VelocimacroProxy object if strVMname is a valid current Velocimacro.

Parameters:

vmName - Name of velocimacro requested

renderingTemplate - Template we are currently rendering. This information is needed when VM_PERM_ALLOW_INLINE_REPLACE_GLOBAL setting is true and template contains a macro with the same name as the global macro library.

template - current template

Returns:

VelocimacroProxy

addVelocimacro

boolean addVelocimacro(String name,
                       Node macro,
                       List<Macro.MacroArg> macroArgs,
                       Template definingTemplate)

Adds a new Velocimacro. Usually called by Macro only while parsing.

Parameters:

name - Name of velocimacro

macro - root AST node of the parsed macro

macroArgs - Array of macro arguments, containing the #macro() arguments and default values. the 0th is the name.

definingTemplate - template containing macro definition

Returns:

boolean True if added, false if rejected for some reason (either parameters or permission settings)

isVelocimacro

boolean isVelocimacro(String vmName,
                      Template template)

Checks to see if a VM exists

Parameters:

vmName - Name of velocimacro

template - Template "namespace"

Returns:

boolean True if VM by that name exists, false if not

getString

String getString(String key)

String property accessor method to hide the configuration implementation

Parameters:

key - property key

Returns:

value of key or null

getInt

int getInt(String key)

Int property accessor method to hide the configuration implementation.

Parameters:

key - property key

Returns:

int value

getInt

int getInt(String key,
           int defaultValue)

Int property accessor method to hide the configuration implementation.

Parameters:

key - property key

defaultValue - default value

Returns:

int value

getBoolean

boolean getBoolean(String key,
                   boolean def)

Boolean property accessor method to hide the configuration implementation.

Parameters:

key - property key

def - default default value if property not found

Returns:

boolean value of key or default value

getConfiguration

ExtProperties getConfiguration()

Return the velocity runtime configuration object.

Returns:

ExtProperties configuration object which houses the velocity runtime properties.

getApplicationAttribute

Object getApplicationAttribute(Object key)

Return the specified application attribute.

Parameters:

key - The name of the attribute to retrieve.

Returns:

The value of the attribute.

setApplicationAttribute

Object setApplicationAttribute(Object key,
                               Object value)

Set the specified application attribute.

Parameters:

key - The name of the attribute to set.

value - The attribute value to set.

Returns:

the displaced attribute value

getUberspect

Uberspect getUberspect()

Returns the configured class introspection/reflection implementation.

Returns:

The current Uberspect object.

getLog

org.slf4j.Logger getLog()

Returns a convenient Log instance that wraps the current LogChute.

Returns:

A log object.

getLog

org.slf4j.Logger getLog(String childNamespace)

Get a logger for the specified child namespace. If a logger was configured using the runtime.log.instance configuration property, returns this instance. Otherwise, uses SLF4J LoggerFactory on baseNamespace + childNamespace.

Parameters:

childNamespace -

Returns:

getApplicationEventCartridge

EventCartridge getApplicationEventCartridge()

Returns the event handlers for the application.

Returns:

The event handlers for the application.

isInitialized

boolean isInitialized()

Returns true if the RuntimeInstance has been successfully initialized.

Returns:

True if the RuntimeInstance has been successfully initialized.

createNewParser

Parser createNewParser()

Create a new parser instance.

Returns:

A new parser instance.

getDirective

Directive getDirective(String name)

Retrieve a previously instantiated directive.

Parameters:

name - name of the directive

Returns:

the directive with that name, if any

Since:

1.6

useStringInterning

boolean useStringInterning()

Check whether the engine uses string interning

Returns:

true if string interning is active

getSpaceGobbling

RuntimeConstants.SpaceGobbling getSpaceGobbling()

get space gobbling mode

Returns:

space gobbling mode